From: Mark Gaffney <markgaffney@mac.com>

Date: January 21, 2009 10:47:08 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: Stupid questions?

Hi Milton, My alignment (PA & otherwise) was good enough at the time to find the object inside the EP reticle & when I lost it out of range & slewed back to it, though not centred there. I wanted to use the brief time I had Saturn "on the chip" to take movies & probably skimped on focusing. Using the direction buttons on the HC to centre it quite often leaves the object beetling out of view in the last adjusted direction! Seeing was quite good I think- I was getting a precise image through the eyepiece at least . With it`s small size (no barlow being used) & distance from me whilst focusing I probably missed this opportunity. I only managed 2 one minute movies & the first it was too high & to the left of the image to stack etc. It was only a first attempt! Though there`s no telling when I`ll get another chance! Mark.

On 22/01/2009, at 4:21 PM, Milton Aupperle wrote:

Hi Mark;  

On 21-Jan-09, at 9:53 PM, Mark Gaffney wrote:

Hi Milton, From what you`ve said here I might be better off using my DBK 21A F04.AS without the Baader filter for Saturn than the Flea 2 colour?

There have been some debates over whether saturn is better or not without an IR filter.

The planets reflect sunlight, so your still getting some IR back from the sun. This might cause focus issues because IR comes into focus at a different point. Also the R G B Bayer filter doesn't filter out IR, which will be seen by the sensor for all colors, which throws the color balance off.

However because it's pretty dim, you might be able to run at lower gains or higher frame rates without an IR filter which helps brighten it up.

You could remove the IR filter on the Flea 2 camera too. The new ones have screws for that, where as for my old Flea camera, I had to dissemble it completely to take the filter off.

I had my first go at Saturn recently with the Flea 2 which I wasn`t terribly excited about. I changed it in processing after seeing Jim Chung`s recent Saturns & posted the result in Photos under my name..."Planetary Images" I think it`s called. I do realise I won`t get results as good through my colour cameras as I would with LRGB imaging.

What was your seeing like? Your ignoring that caveat. If your seeing is poor, it doesn't matter if your using mono LRGB or Bayer Color camera.

I may have been slightly out of focus with my shot as well, my monitor being 2-3 metres from the scope & focusing knob.

For maximum image quality you have to have perfect focus and have your SCT or Newt scope very well collimated.

It was difficult keeping the object still for the 1 minute movies I took also & I was conscious that if I changed focus mid-movie my stacking & aligning mightn`t work. Thanks, Mark.

Actually if you move it out of focus while imaging, it will just be treated as blurry images from turbulence.

For planets, I usually shoot multiple movies and change focus in between each one.

I also find it helpful to use a reasonably bright adjacent star for focus instead of the planet. Especially for Jupiter which I find difficult to judge sharpness on except on very still nights.

HTH..

Milton J. Aupperle